1. Field of the Invention
The invention relates to an inductively-coupled high density plasma producing apparatus and plasma processing equipment provided with the same, and more particularly to an inductively-coupled high density plasma producing apparatus which includes a shape-adjustable coil for increasing the adjustable ranges of control parameters in the semiconductor processing, and the plasma processing equipment provided with them same.
2. Description of the Related Art
In the semiconductor process, such as etching, chemical vapor deposition, sputtering, and photoresist removing, the plasma source, i.e., a plasma producing apparatus has been widely used. Furthermore, in line with the continuous developments of technology, the plasma source with a low plasma density is increasingly replaced by one with a high plasma density. The characteristics of the plasma, especially the uniformity of the plasma density, extremely affect the quality of products. A poor plasma density not only causes a poor uniformity of layers formed in the semiconductor process, but damages the formed devices, thereby resulting in a poor yield. In addition to a number of processing parameters, such as components of the gas, pressure, plasma source, RF power bias of a wafer stage, it is found that designs of the plasma chamber can also affect the uniformity of the plasma. Moreover, even though the processing parameters, such as pressure, voltage, gas flow, can be adjusted to make the plasma as uniform as possible in coordination with different processes, the adjustable ranges thereof are completely different in light of different processes. Therefore, the adjustable ranges of the processing parameters become are limited. As a result, it is impossible to obtain a satisfied plasma uniformity if the processing parameters are out of the adjustable ranges.
To overcome this problem, various approaches are used to obtain a satisfied uniformity of plasma instead of controlling the parameters. For example, a conventional parallel-plate plasma etching machine has been disclosed in U.S. Pat. No. 4,626,312. The disclosed etching machine includes an upper electrode and a lower electrode, and a wafer is placed on the lower electrode, between which the plasma being produced by the supply of an RF power. Furthermore, a planar coil used to increase the uniformity of the plasma has been disclosed in U.S. Pat. No. 4,948,458. A conventional magnetically-coupled plasma producing apparatus 10 is shown in FIG. 1. The plasma producing apparatus 10 is mounted on a housing 12 and includes a primary coil 36 for receiving an RF power, a secondary planar coil 20 which is coupled to the first primary coil 36 to produce an electromagnetic field in a plasma chamber, and a variable capacitor 44 for a matching adjustment.